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What Have You Changed Your Mind About?

The mark of a scientist is being able to change his
or her mind in light of new evidence, but when the online intellectual
salon edge.org chose as its annual
question, “what have you changed your mind about? why?,” I confess I
didn’t have very high hopes for what the biologists, physicists and
other scientists who post to the site would come up with.

In my line of work, if you are looking for a scientist who can argue
the merits of genetically-modified crops, the details of human evolution
or any other question, it is as rare as hens’ teeth to hear that the
position the scientist currently holds is not the one he or she held in
the past. Members of the species Homo scientificus just don’t change their individual minds (though the community does; that’s what we call scientific revolutions, as per Thomas Kuhn. Something to do with being identified with, and having an intellectual stake in, a certain position, I guess.

So it was refreshing that of the 119 (as I write this on New Year’s
Eve day) scientists weighing in on edge.org, at least half a dozen had
surprisingly humble, refreshing new thoughts on long-entrenched
positions. You can read the scores of answers yourself (though I do not
recommend it as a hangover cure), but these are my favorites:

Psychologist Steven Pinker
of Harvard will astonish anyone who has followed his work in
evolutionary psychology, which argues that the human mind was shaped by
the evolutionary pressures that existed during the Stone Age. Thanks to
these selective forces, men are predisposed (evo pysch-ists stop short
of saying “hard-wired”) to mate with as many women as possible, women
are predisposed to be coy and monogamous, men are jealous of sexual
infidelity and women of emotional infidelity, men are predisposed to
kill their stepchildren, on and on. As Pinker wrote a decade ago in his
book “How the Mind Works,” for 99 percent of human existence, “people
lived as foragers in small nomadic bands. Our brains are adapted to that
long-vanished way of life, not to brand-new agricultural and industrial
civilizations,” and humans have essentially stopped evolving
biologically.

Now, says Pinker, “though I stand by a lot of those statements, I've
had to question the overall assumption that human evolution pretty much
stopped by the time of the agricultural revolution.” Instead, recent
genetic findings show that thousands of human genes have evolved since
then. If so, then—drum roll, please—“evolutionary psychology might have
to reconsider the simplifying assumption that biological evolution was
pretty much over and done with 10,000-50,000 years ago.” Pinker suspects
that will not lead to “radical” revisions of our understanding of human
nature, which he argues is deeply similar across cultures (others, of
course, disagree). But if our minds are not creatures of the Stone Age,
then many of the darker aspects of human nature that evo psych has
always argued are our lot might be no more so that Neanderthalian brow
ridges.

A number of scientists are waving the white flag when it comes to the
power of reason over superstition. One of the strongest arguments for
scientific literacy has long been that if people knew a little biology,
chemistry and physics, they would not be taken in by health quacks or
get swindled by tarot-card readers and other pseudoscientific offerings.
But as neuroscientist Marco Iacoboni [iacoboni.bmap.ucla.edu/] of UCLA
admits, “Some time ago I thought that rational, enlightened thinking
would eventually eradicate irrational thinking and supernatural beliefs.
. . . [But 30 years later,] irrational thinking and supernatural
beliefs are much stronger than they used to be, permeat[ing] ours and
other societies.” He blames the fact that science has only a marginal
role in public discourse (“there are no science books on the New York
Times 100 Notable Books of the Year list”), partly because scientists
tend to “marginalize themselves and make it difficult for science to
have an impact on their society.” He suggests that this dreary picture
will improve if scientists “step up and claim wisdom outside their
specialty.”

Really? Molecular biologist Lee Silver of
Princeton has his doubts. He once thought that "if we could just get
people to understand the science, they’d agree with us, . . . [and that]
“modern education would inevitably give rise to a populace that
rejected the idea of a supernatural soul.” No more. He has had too many
encounters with “well-educated defenders of the irrational . . . about a
host of contentious biological subjects including evolution, organic
farming, homeopathy, cloned animals, ‘chemicals’ in our food, and
genetic engineering. Much to my chagrin, even after politics, ideology,
economics, and other cultural issues have been put aside, there is often
a refusal to accept scientific implications of rational argumentation.”
As he sadly concludes, “irrationality and mysticism seem to be an
integral part of normal human nature, even among highly educated people.
No matter what scientific and technological advances are made in the
future, I now doubt that supernatural beliefs will ever be eradicated
from the human species.”

In a related vein, physician and social scientist Nicholas Christakis of
Harvard is now questioning the supremacy of genes over culture, saying
that he has changed his mind about whether “culture can change our
genes.” Like Pinker, he now believes that “human evolution may proceed
much faster than I had thought.” Even more intriguing, “humans
themselves may be responsible.” In societies where a stable supply of
milk is available, for instance, people evolve genes making them
lactose-tolerant, as has occurred in just the last 3,000 to 9,000 years
several times in Africa and Europe. In societies where population
density is high enough to spread epidemic diseases such as typhoid, some
populations evolve genes that confer resistance to the disease.

Christakis concludes, “It is hard to know
where this would stop. There may be genetic variants that favor survival
in cities, that favor saving for retirement, that favor consumption of
alcohol, or that favor a preference for complicated social networks.
There may be genetic variants (based on altruistic genes that are a part
of our hominid heritage) that favor living in a democratic society,
others that favor living among computers.”

One can detect a whiff of revolution in the air. Harvard biologist Marc Hauser says
he has changed his mind about “Darwinian Reasoning.” No, he has not
become a creationist, but is now more skeptical of the dogmatic view
that all traits are adaptive. "In recent years, I have made less use of
Darwin’s adaptive logic,” Hauser writes. “It is not because I think that
the adaptive program has failed, or that it can’t continue to account
for a wide variety of human and animal behavior. But with respect to
questions of human and animal mind, and especially some of the unique
products of the human mind—language, morality, music, mathematics—I
have, well, changed my mind about the power of Darwinian reasoning. . . .
[W]here I have lost the faith, so to speak, is in the power of the
adaptive program to explain or predict particular design features of
human thought. Although it is certainly reasonable to say that language,
morality and music have design features that are adaptive, that would
enhance reproduction and survival, evidence for such claims is sorely
missing.”

For those of you with long memories of what
were called the evolution wars before that term was co-opted by
evolution vs. creationism battles, look up the classic 1979 paper by Stephen Jay Gould and Richard Lewontin on spandrels. It will be interesting to see if more biologists reject the strict adaptationist paradigm.

The edge.com forum is sprinkled with other nuggets of mind-changing. Read why psychologist David G. Myers of
Hope College now believes that “newborns are not the blank slates I
once presumed, . . . economic growth has not improved our morale, the
automatic unconscious mind dwarfs the controlled conscious mind,
traumatic experiences rarely get repressed, personality is unrelated to
birth order, . . . opposites do not attract, [and] sexual orientation is
a natural, enduring disposition (most clearly so for men), not a
choice.”

Moving from biology to physics, cosmologist Paul Steinhardt
of Princeton no longer believes that cosmic inflation created the
structure of the universe, and now feels “compelled to seek a new
explanation that may or may not incorporate inflation. . . . Quantum
physics turns out to play an absolutely dominant role in shaping the
inflationary universe. In fact, inflation amplifies the randomness
inherent in quantum physics to produce an universe that is random and
unpredictable. . . . Speaking for myself, it may have taken me longer to
accept its quantum nature than it should have, but, now that facts have
changed my mind, I cannot go back again. Inflation does not explain the
structure of the universe.”

Edge is the brainchild of New York literary
agent and “third culture” impresario John Brockman. The third culture, a
term he coined, “consists of those scientists and other thinkers in the
empirical world who, through their work and expository writing, are
taking the place of the traditional intellectual in rendering visible
the deeper meanings of our lives, redefining who and what we are.” For
this year’s question, his third-culturati really came through.